1. Field of the Invention
The present invention relates to an X-ray diagnosis apparatus and an image processing apparatus.
2. Description of the Related Art
A treatment method called vascular intervention treatment has been conventionally performed on a stenosed portion occurring in a blood vessel caused by, for example, a thrombus.
According to vascular intervention treatment, a balloon-tip catheter is inserted by a doctor up to a stenosed portion. A liquid is then injected into the balloon through the catheter, so that the balloon is expanded, as a result, the stenosed portion is mechanically expanded. After the liquid in the balloon is sucked out, the balloon-tip catheter is withdrawn by a doctor to the outside of the body.
To avoid re-stenosis of the stenosed portion that is expanded with the balloon, vascular intervention treatment with the use of a balloon-tip catheter tightly attached with a stent strut of metal mesh around the outer side of the balloon is also performed. According to such treatment method, after the stent strut is expanded along with expansion of the balloon, the balloon-tip catheter is withdrawn to the outside of the body by sucking out the liquid in the balloon. Consequently, the expanded stent strut is retained in the stenosed portion, thereby reducing a re-coarctation rate in stenosed portion. A device that includes two parts, namely, a stent strut and a balloon-tip catheter, is called a “stent”.
According to the vascular intervention treatment described above, an X-ray diagnosis apparatus performs fluoroscopic imaging of a treatment target portion, and a doctor remotely executes a series of processing with the use of a balloon-tip catheter and a stent while referring to an X-ray image displayed on a monitor.
The vascular intervention treatment requires precisely moving a balloon-tip catheter and a stent inserted in a blood vessel to a treatment target portion. Particularly when retaining a stent strut, it is required to position the stent precisely by millimeter. For this reason, the balloon part is attached with an X-ray impermeable metal at two points (or one point in some cases) as a marker that indicates the position of a balloon-tip catheter or a stent (stent marker), and a doctor performs treatment while confirming the position of the balloon-tip catheter or the stent by referring to a stent marker on a displayed X-ray image.
However, when performing vascular intervention treatment on a blood vessel in an organ that is constantly throbbing, such as a heart, the position of a balloon-tip catheter and the position of a stent on an X-ray image constantly move, therefore, it is a very high-technique operation for a doctor to perform positioning by referring to an X-ray image.
Although edge parts of a stent strut are important for a doctor to determine an extent of expansion of the stent strut, X-ray impermeability of a stent strut is very low compared with X-ray impermeability of a stent marker. For this reason, the edge parts of a stent strut are less clear than a stent marker.
Therefore, as a technology for improving visibility of a stent on an X-ray image, a stent-highlighted display technology (for example, see JP 2005-510288 (KOKAI)) is proposed.
According to the stent-highlighted display technology, a plurality of frames of X-ray images of a treatment target portion is taken along a time sequence, and correction is performed on the taken X-ray images so as to match up the position of a moving stent by using a stent marker as a reference. Processing, such as adding and averaging, is then performed on the X-ray images on which movement correction is performed, and then a highlighted image on which the stent strut is highlighted is created.
Specifically, as shown in FIG. 22, correction processing is performed on a second frame so as to match up the positions of stent markers in the second frame with the positions of the stent markers in a first frame. Such correction processing is performed on a plurality of frames (for example, up to a 30th frame), and adding and averaging processing is performed on a plurality of images on which the positions of the stent markers match up. Accordingly, as shown in FIG. 22, a highlighted image on which the stent strut is highlighted and the whole stent is clearly rendered is created, and the created highlighted image is displayed on a monitor. FIG. 22 is a schematic diagram for explaining the conventional technology.
The conventional technology described above has a problem that an X-ray image that ensures visibility of treatment equipment, such as a stent, cannot be instantly displayed at the time of execution of vascular intervention treatment performed with reference to an X-ray image.
In other words, according to the stent-highlighted display technology described above, visibility of a stent can be improved; however, because tracking processing of stent marker, correction processing, and creating processing of highlighted image are performed as post-processing after a plurality of X-ray images is created along a time sequence, a waiting time (for example, tens seconds of waiting time) arises from imaging of an X-ray image until display of a highlighted image. Furthermore, because a highlighted image is created only one frame from a plurality of images (for example, 30 frames) on which correction processing is performed, temporal resolution of a displayed highlighted image is lower than temporal resolution of taken X-ray images.
Similarly to the case of performing vascular intervention treatment, any case of treatment performed by a doctor referring to an X-ray image with the use of treatment equipment (for example, rotablator) attached with X-ray impermeable marker and arranged in a treatment portion that moves continuously due to throbs has a problem of incapability of instantly displaying an X-ray image that ensures visibility of the treatment equipment, even by using the conventional technology described above.
For this reason, the present invention has been made to solve the problems of the conventional technology described above, and an object of the present invention is to provide an X-ray diagnosis apparatus and an image processing apparatus that can instantly display an X-ray image that ensures visibility of treatment equipment at the time of execution of a treatment performed with reference to an X-ray image.